1. Field of the Invention
The present invention relates to an electron-emitting device, an electron source, and a method of producing an image display device.
2. Description of the Related Art
The electron-emitting device includes an electron-emitting device of a field emission type (hereinafter, referred to as “FE type”) and an electron-emitting device of a surface-conduction type disclosed in Japanese Patent Application Laid-Open No. H10-055753.
The FE type includes an electron-emitting device using a carbon fiber disclosed in K. B. K. Teo and eight others, Field Emission from Dense, Sparse and Patterned Arrays of Carbon Nanofibers, “Applied Physics Letters”, Mar. 18, 2002, Vol. 80, P. 2011 to 2013, Japanese Patent Application Laid-Open No. 2002-140979, and Japanese Patent Application Laid-Open No. 2004-107162, and an electron-emitting device having an electron emission film with a flat surface disclosed in Japanese Patent Application Laid-Open No. 2004-071536, Japanese Patent Application Laid-Open No. H08-055564, and Japanese Patent Application Laid-Open No. 2005-026209.
As an example of the electron-emitting device having few spread of the electron beam to be emitted, there are an electron-emitting device provided with an aperture (so-called “gate hole”) on a flat electron emission film and having a laminate with an insulating layer and a gate electrode. In the electron-emitting device having such a flat electron emission film, since a relatively flat equipotential surface is formed on an electron emission film surface, the spread of the electron beam can be made small. Further, Japanese Patent Application Laid-Open No. H08-055564 and Japanese Patent Application Laid-Open No. 2002-140979 propose an electron-emitting device which disposes a conductive layer on the electron emission film to make the spread of the emitted electron beam small. Japanese Patent Application Laid-Open No. 2004-071536 and Japanese Patent Application Laid-Open No. 2005-026209 propose an electron-emission film containing metal excellent in electron emission characteristic and an electron-emitting device using the electron emission film provided with a dipole layer on the surface.
Further, Japanese Patent Application Laid-Open No. H10-064416 discloses a process in which an alkali metal intended to be an acceptor is provided on the surface of a semiconductor to make the surface vicinity of the semiconductor into a strong p-type, and then, the alkali metal is diffused into the semiconductor. Specifically, Na2Se or K2S is thinly vapor-deposited on the semiconductor surface of ZnS, Na2Se or K2Se on the semiconductor surface of ZnSe, and Na2Te or K2Te on the semiconductor surface of ZnTe or CdTe. Japanese Patent Application Laid-Open No. H10-064416 discloses that the alkali metal is heated at 500 to 600° C. in an inactive gas so that alkali metal is diffused into the semiconductor.
A method of forming the electron emission film containing metal excellent in electron emission characteristic as disclosed in Japanese Patent Application Laid-Open No. 2004-071536 includes various methods such as a method of sputtering metal and graphite simultaneously, a method of sputtering a mixed target of metal and graphite, and a method of ion-implanting metal into a carbon thin film. However, these methods are complicated in a producing step. Further, to stabilize the electron emission characteristic of the electron emission film, it is important to control a metal amount in the electron emission film. Further, when adhesiveness between the electron emission film and a layer (for example, a cathode electrode) in contact with the electron emission film is bad, due to heat and the like generated in various steps of the production time and during driving, the electron emission film may be peeled off in an extreme case, thereby causing various problems.
Hence, an object of the present invention is to provide a method of producing an electron-emitting device, which can be easily fabricated and can relatively easily control an amount of metal in the electron emission film, and in which the adhesiveness between the electrode and the like in contact with the electron emission film and the electron emission film is good. Another object of the invention is to provide a method of producing an electron-emitting device in which electron emission characteristic is stabilized and spread of electron beam is small. Further, another object of the invention is to provide a method of producing an electron source having a great number of electron-emitting devices and a method of producing an image display device using the electron source.